Vessel Operations

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7.1 Tactical Navigation - Encountering Negative Ice Numerals

At certain points in a voyage, it may be essential to transit local areas where the regime has a negative Ice Numeral for the ship. This should not form part of a voyage plan.

While using the Ice Regime System, intentional entry into a negative ice regime outside the Zone/Date limits is prohibited.

Examples of this situation may develop when the ship has been following a voyage plan that was based on either ice information in which the resolution of the data used to compile the chart is larger than the local floe sizes or simply old ice information. Another consideration is that by the very definition of an “Ice Regime”, there could be several regimes at the tactical level that may not appear on ice charts due to the scale and detail required to indicate every ice regime down to the vessel’s level. Another scenario may find the ship unable to avoid deteriorating conditions during the later part of the season when the ice is likely to grow rather than dissipate.

When the Master or Ice Navigator find themselves in any of the above situations they may consider:

  1. selecting another route,
  2. obtaining more recent and / or higher quality ice information,
  3. waiting for improved weather or ice conditions, or
  4. requesting the assistance of an icebreaker by calling NORDERG .

NORDREG , will be able to provide additional information to assist in these circumstances and will have up-to-date knowledge of the positions of icebreakers. As a reminder, comments related to such situations must be incorporated into the After Action Report when operating outside of the Zone / Dates.

7.2 Escorted Operations

When ice conditions prevent, or significantly impede a ship's operations, it may be desirable or necessary to work together with another vessel of similar capability, or to be escorted by one of greater capability. Escorted operations are specifically allowed for in the Ice Regime System, and must be considered on an individual basis while planning routes and defining local ice regimes. Under some circumstances a suitable escort can be effective in easing the ice conditions along the route (for example, breaking large pieces of dangerous ice or assisting vessels to manoeuvre around them). However, if the escort’s broken track is too narrow, if the ice is under pressure, or if there are various other circumstances, the effectiveness of an escort can be severely limited.

The ice regime that has been modified by the suitable escort should be the basis for the decision on whether to proceed.

The Masters of both the escort and the escorted ship must work closely. The icebreaker will decide whether it is safe to break a track, but the Master of the escorted ship must continue to evaluate the conditions in order to decide whether it is safe to follow, and at what speed. Communications and operating procedures must be established before any escort operation starts and maintained throughout. There may also be the requirement for an Escort Message (Section 4.0, Part B) to be sent to the icebreaker. In the publication, Ice Navigation In Canadian Waters (Section 2.7.2), there is information on the recommended procedures for icebreaker escort operations.

Issues to consider regarding the escort operation:

  • the width of the broken track, in comparison with the following ship's beam,
  • the size, thickness, and strength of the ice pieces left in the track,
  • the likelihood of pressure conditions, which may cause the track to close rapidly.

7.2.1 Calculating an Ice Numeral Behind an Escort

The track of an escort and surrounding conditions should be treated as a separate Ice Regime, while the Ice Numeral calculation process remains the same. The ice in the track must be assessed for thickness (age / ice type), concentrations and floe size. If the actual floes are under 2  m in diameter, consider it ‘Brash’ with an Ice Multiplier equivalent to Open Water, i.e. +2. When adding up the 10th’s of Brash and Open Water, a positive regime is possible, but it is not necessarily indicative of a safety factor.

Extreme caution must be exercised when working in an Icebreaker’s track because of the confined aspect of the track. Ice floes, although small could be several metres thick and have no place to go other than being pushed ahead in the track, under the ice sheet or forcibly wedged between the ship’s side and the ice edge.

Maintain a watch for the use of either the icebreaker’s red Escort Warning Lights or the aft facing Zet Horn.

7.3 Early Season Voyage

An early season voyage can be described as a voyage where the vessel intends to enter the Canadian Arctic prior to the main onset of melt and expects to actively break ice to reach its destination. Depending on the area, early season voyages are those in May, June, or early July.

Prior to departure, a vessel planning an early season voyage may contact the Canadian Ice Service to receive a copy of the Seasonal Outlook, and the Thirty Day Forecast (see Section 4.5 in this document for addresses and phone numbers). As the vessel proceeds towards the Canadian Arctic, the noted HF facsimile frequency should be monitored in order to receive the most recent Daily Ice Analysis charts or Ice Edge charts. (Refer to Radio Aids To Marine Navigation)

When the vessel is approximately 24 hours away from the Shipping Safety Control Zones, the vessel is to send an Ice Regime Routing Message to NORDREG (Section 4.2). NORDREG will reply with a message that acknowledges that the vessel will be entering the Arctic Canada Traffic Zone, and it may also contain a recommended route for the vessel.

Once the vessel is north of 60° N latitude reporting to NORDREG should continue in the form of the daily 1600 UTC Reports. HF facsimile broadcasts and radio transmissions of ice forecasts should continued to be monitored to receive the latest ice information.

On early season voyages, a vessel may wish to enter a zone outside the Zone / Date System. Entry could be possible under the Ice Regime System if there is an indication of positive Ice Numerals. In this case it will be necessary for the vessel to have on board an Ice Navigator. An Ice Regime Routing Message must be sent to NORDREG via the nearest Marine Communications and Traffic Services Centre and following the voyage an After Action Report (as described earlier in Section 5.2) must be submitted. It should be remembered that during the transition period the After Action Report is always required whenever the Ice Regime System is used even though only positive Ice Numerals may have been encountered.

During an early season voyage, conditions will generally be improving due to the longer days and the sea ice undergoing its decay process. Thus, although delays in transit on an early season voyage may be undesirable, detouring or waiting for conditions to improve may be the safest and most efficient option.

7.4 Late Season Voyage

Late season voyages (late October-November) deserve special attention because of the certainty that ice conditions will worsen during the voyage, and the possibility that they will deteriorate rapidly. Severe, late season storms can cause pressure events and move large quantities of Multi-Year ice from high latitudes into the shipping channels. An example of this phenomenon is the redistribution of Multi-Year ice from the Kane Basin / Smith Sound to along the western shore of Baffin Bay, including the formation of a North / South barrier of ice that may block the entrance to Lancaster Sound.

Prior to departure, a vessel planning a late season voyage may contact the Canadian Ice Service to receive a copy of the Seasonal Outlook, and the Thirty Day Forecast (Section 5.5). As the ship heads toward the Arctic, the appropriate HF facsimile frequency should be monitored in order to receive the most recent Daily Ice Analysis charts or Ice Edge charts. (Refer to Radio Aids To Marine Navigation)

When the vessel is approximately 24 hours away from the Shipping Safety Control Zones, the vessel is to send an Ice Regime Routing Message to NORDREG (Section 4.2). NORDREG will reply with a message that acknowledges that the vessel will be entering the Arctic Canada Traffic Zone, and it may also contain a recommended route for the vessel. On late season voyages this communication with NORDREG is very important considering that the availability of Icebreaker support may be crucial if ice conditions deteriorate rapidly.

Contact may also be made on HF with other ships or icebreakers in the area as these ships may be able to provide additional ice information or support if required.

With these voyages, a vessel may wish to enter a zone outside the Zone / Date System and entry is permitted under the Arctic Ice Regime Shipping System provided that several conditions are met. The ship will be required to have an Ice Navigator on board (see Section 7.2), submit an Ice Regime Routing Message that illustrates positive ice regimes ahead of the vessel, and provide an After Action Report 30 days after departing NORDREG ’s waters. Assistance in these areas may be found by contacting NORDREG via the nearest Marine Communications and Traffic Services Centre.

In most cases a Coast Guard icebreaker is on standby for ships operating in the Arctic late in the season.

7.5 Tug and Barge Operations

The AIRSS Standards ( TP 12259) do not fully address several aspects of towing operations such as the reduced icebreaking capability of a vessel engaged in towing, the increased potential for collision between tug and tow and the constraints imposed on the route by the size and manoeuvrability of the tow relative to the characteristics of the tug1.

Unlike the simple Ice Numeral calculation required for a single ship to enter an ice regime, when a tug and tow combination are about to enter a regime there must be some consideration made for the hull strength or Ice Class of both the tug and each component of the tow. From a structural perspective the set of Ice Multipliers selected should correspond to the lightest structure / ice class in the towing operation and the towmaster should make frequent inspections to check for evidence of damage during the tow. Prior to entering the ice, some of the factors to consider should be:

  • the quality (date / resolution / source) of the ice information available,
  • the reduced icebreaking capability of the tug while engaged in towing1,
  • the method of towing1 (close-couple or conventional),
  • the beam and displacement differences between the tug and tow1,
  • the floe sizes of the ice1 and indication of pressure, and
  • the effectiveness of the ice escort1, if any.

Tug and barge operations and other tows in the Arctic require particular care. Directional control may be difficult, while the speed of both the towing ship and its tow can change almost instantly, thus increasing the risk of collisions with ice floes. Selection of appropriate tow lengths and speeds therefore requires experience, understanding, and caution.


M/V TERRY FOX Towing the ARCTIC KIGGIAC, 1991 Photo: B. Cowper
1 Draft - Operational Review of the Arctic Ice Regime Shipping System standards for Tug and Tow Operations,
Pages 1 & 2, March 1997

7.6 Crew and Equipment

Any ship planning to enter the Arctic should have an adequate crew, and the equipment should be suited to the voyage and the environmental conditions which will be encountered. The prevention of damage to the hull and propulsion machinery by ice requires navigation with due caution, as described earlier. Mariners should also be aware that vibration during icebreaking can put high stresses on equipment, causing breakdowns or malfunctions. Hull vibrations can also have deleterious effects on personnel. Any ship making a maiden voyage into Arctic waters may have unexpected problems, and should have contingency plans to cover repairs or delays.

Natural phenomena can make it difficult to get good performance from communications or navigation equipment. The most common of these problems are the speed (especially the East/West component) and damping of the gyros, magnetic variation, ionospheric disturbances that may affect radio transmissions, and obtaining an unobstructed view of an INMARSAT satellite above 73° North.

Navigating in the Arctic can be very demanding and tiring. If an operator plans to navigate for prolonged or difficult periods of ice navigation while using the Arctic Ice Regime Shipping System it may consider it prudent to assign sufficient Ice Navigators1.

Few Arctic ports and terminals have comparable facilities to those found in Southern areas. The crew and equipment carried should therefore be adequate in numbers and training to handle any challenges which may arise. Masters should ensure that they are fully aware of the shore facilities available when making their voyage plans.

For voyages involving an oil transfer to or from the ship, specific requirements for crew and equipment may apply depending on the transfer location. Details are given in Arctic Waters Oil Transfer Guidelines, TP 10783. (See the List of Reference Material in Section 8.2 for information on obtaining a copy.)

Other important equipment items to consider are those involving safety and emergency response. Masters should be aware that voyages at any time of year may encounter difficult conditions, and those in winter months can involve extremely low temperatures. Standard safety equipment may not function properly under these conditions, or may not be adequate to ensure protection.

Transport Canada has developed a Cold Weather Marine Survival Guide, TP 11690, and a Marine Survival Handbook for Cold Regions, TP 11969. These provide details and a summary, respectively, of practical advice on cold weather survival in a marine environment. Masters planning Arctic voyages should be familiar with these publications, and should ensure that copies are made available to be read by personnel on board.



1. On the topic of Ice Navigation being demanding and tiring, the following research and development report addresses this issue: Hours of Work and Rest of Canadian Ice Navigators on board Foreign Registered Vessels in Arctic Waters, Page 17, Section 4.2.5, March 1998, TP 13207 E



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